Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual é o número aproximado de HUs quando há mais de 2 dígitos e 6 níveis?
 ###Tabelas: CREATE TABLE north_carolina_counties_ranked_by_per_capita_income (north_carolina_counties_ranked_by_per_capita_income_id AUTO_INCREMENT PRIMARY KEY, County VARCHAR, Per capita income VARCHAR, Median household income VARCHAR, Median family income VARCHAR, Population INT, Number of households INT) CREATE TABLE week_four (week_four_id AUTO_INCREMENT PRIMARY KEY, Date VARCHAR, Time VARCHAR, Visiting team VARCHAR, Home team VARCHAR, Site VARCHAR, Broadcast VARCHAR, Result VARCHAR, Attendance INT) CREATE TABLE united_states (united_states_id AUTO_INCREMENT PRIMARY KEY, Name VARCHAR, Level INT, Digits INT, Average size (square miles) VARCHAR, Number of HUs (approximate) INT, Example name VARCHAR, Example code (HUC) INT) CREATE TABLE season_2_1995–1996 (season_2_1995–1996_id AUTO_INCREMENT PRIMARY KEY, Series # INT, Season # INT, Title VARCHAR, Directed by VARCHAR, Original air date VARCHAR, Production code VARCHAR) CREATE TABLE 2009_2010_table (2009_2010_table_id AUTO_INCREMENT PRIMARY KEY, Club VARCHAR, Played VARCHAR, Drawn VARCHAR, Lost VARCHAR, Points for VARCHAR, Points against VARCHAR, Tries for VARCHAR, Tries against VARCHAR, Try bonus VARCHAR, Losing bonus VARCHAR, Points VARCHAR)  
SELECT COUNT Number of HUs (approximate) FROM united_states WHERE Digits > 2 AND Level = 6